Rotary regenerative heat exchangers



y 1967 H. SANDMANN 3,319,705

ROTARY REGENERATIVE HEAT EXCHANGERS Filed Sept. 27, 1965 5 Sheets-Sheet l 2'7. 26$ 80 I I l I v} I I I m 39 l I I l L I IN V E /V 7' 0 I? HERBERT SAND/MW ROTARY REGENERATIVE HEAT EXCHANGERS May 16, 1967 Filed Sept.

INVEA/To 1? HERBERT SANDM/M/A/ l- I213 W 64/ May 16, 1967 H. SANDMANN ROTARY REGENERATIVE HEAT EXCHANGERS 5 Sheets-Sheet 5 Filed Sept. 27, 1965 jI/v VEIVTO R HE I? BE K T SAND/MAW United States Patent 3,319,705 ROTARY REGENERATIVE HEAT EXCHANGERS Herbert Sandmann, ()lpe, Westphalia, Germany, assignor to Apparatcbau Rothemuhle Brandt & Kritzler, Glpe, Westphalia, Germany, a company of Germany Filed Sept. 27, 1965, Ser. No. 490,326 Claims priority, application Germany, Sept. 29, 1964, A 22,505 4 Claims. (Cl. 165-4) This invention relates to rotary regenerative heat exchangers of the kind in which a substantially cylindrical regenerative heat exchange member, hereinafter referred to as a regenerator, is disposed stationary within an outer casing which has gas inlet and gas outlet means at its ends or otherwise suitably located whereby hot gas may be led to the regenerator and passed in an axial direction through passages in the regenerator so as to give up heat from the said hot gas to a mass of plates or tubes which form the passages. Also disposed within the casing, and at each axial end of the regenerator, are rotatable duct members provided with means to lead air to one of the said duct members and from the other said duct member after passing in an axial direction through the regenerator, the said duct members rotating co-axially in relation to the stationary regenerator and having openings which pass over the end surfaces of the regenerator during such rotation, the opening or openings in one of the two duct members being disposed in mirror-image relation to the opening or openings in the other duct member so that air may flow direct from one duct member, through part of the regenerator mass to pick up heat from said mass, and then into the other duct member.

Usually the said openings in the duct members are of sector shape, and there may be one or more such openings in each duct member.

It is desirable that the ends of the rotatable duct members which sweep over the ends of the stationary regenerator should do so in such manner that there is the minimum amount of leakage between the duct members and the enclosing casing, and usually this has been effected by sealing members, sometimes spring-pressed, disposed at the edges of said duct openings so as to be pressed into contact with the end surfaces of the regenerator. It also has been proposed that the shaft which passes axially through the stationary regenerator and is connected to the two rotatable duct members should be provided with axially movable means to allow the two duct members and their sealing members to be retained in sealing engagement with the end surfaces of the regenerator during all phases of heat expansion.

Such rotary regenerative heat exchangers are referred to hereinafter as of the kind referred to.

The means for effecting and retaining a gas and air seal between the rotatable duct members and the end surfaces of the regenerator have comprised a sealing member at each rotatable duct for facial engagement with a regenerator end surface, a frame carrying the sealing member, a gas-tight flexible and resilient expansion joint device between the rotatable duct and the sealing member frame, swivelling joint means also between the rotatable duct and the sealing member frame, and spring means for urging the sealing member frame toward the regenerator.

The object of the present invention is to provide improvements in respect of the adjustment of means for limiting the pressure applied to the sealing member frame toward the regenerator by the spring means.

According to this invention, a rotary regenerative heat exchanger comprising a casing, a hot gas inlet chamber at one end of said casing, a gas outlet chamber at the other end of said casing, a stationary regenerator within 3,319,795 Patented May 16, 1967 said casing between said chambers, a mass of plates in said regenerator providing a multiplicity of axial passages therethrough, an outlet air duct one open end of which is disposed within said gas inlet chamber, an inlet air duct one open end of which is disposed within said gas outlet chamber, rotatable air duct members at each axial end of said regenerator having necks disposed in rotatable air and gas tight engagement with the open ends of the inlet and outlet air ducts, each air duct member having duets with openings at their ends adjacent the axial end faces of said regenerator whereby air emitted from said inlet air duct passes through said regenerator into said outlet air duct, and sealing assemblies disposed around the peripheries of the openings of said air duct members, each sealing assembly comprising a sealing member, a frame attached to said sealing member, an expansion member between said air duct member and said frame, swivel joint means between said air duct member and frame for transmitting the rotational movement of said air duct members to said sealing member, and resilient means urging said frame from said air duct members toward said regenerator, said resilient means comprising a series of bolts disposed at spaced intervals around and secured to said frame, spring means around each said bolt and urging the bolt axially thereof together with the said frame towards the regenerator, each bolt passing freely through a flange on the air duct member, the end of the bolt remote from the said frame being provided with a flange which normally is disposed with a clearance from the flange on the air duct member and is adapted to abut said flange on the air duct member whereby to limit said axial movement of the bolt, is characterised in that a slide of appropriate thickness is placed between the flange on the bolt end and the flange on the air duct member whereby to adjust the dimension of the said clearance to a desired amount of, for example, 0.5 mm.

In the accompanying drawings:

FIG. 1 is a diagrammatic sectional elevation of a rotary regenerative heat exchanger of the kind referred to;

FIG. 2 is an enlarged fragmentary sectional'elevation of a sealing member, its frame, a rotatable air duct and other related elements, including a flexible and resilient expansion joint device, and including part of adjustable pressure limiting means according to one embodiment of the invention;

FIG. 3 is an elevation of the swivelling joint means, looking in the direction of arrow III in FIG. 2;

FIG. 4 is a View similar to a portion of FIG. 2, but showing the complete adjustable pressure limiting means;

FIG. 5 is a sectional elevation taken on line V-V of FIG. 2;

FIG. 6 is a sectional elevation taken on line VI-VI of FIG. 4;

FIG. 7 is a perspective view of a slide.

Referring to FIG. 1, a casing 11 provides at its top end a chamber 12 into which hot gases, from a suitable source, are admitted by means not shown, and the casing also has at its bottom end a chamber 13 from which the said gases, after giving up heat to the regenerator hereinafter referred to, are withdrawn by means not shown.

Between the chambers 12 and 13 there is a stationary cylindrical regeneratior 14 which is provided with plates or tubes which provide a mass 15 which forms passages which are open at the ends of the regenerator. Thereby, the hot gas from the chamber 12 may flow through the mass 15, give up heat to the said mass, and then pass on, as cool gas, to the chamber 13.

Within the chamber 12, and co-axial with the regenerator 14, there is the open end 16 of an outlet air duct 17, whilst within the chamber 13 there is a similar open end 18 of an inlet air duct 19.

Below the regenerator 14 there is an air duct member 20 which has an axial neck 21 which is disposed in rotatable, air and gas tight, engagement with the end 18 of the air duct 19, and has ducts 22 and 23 which have sector-shaped openings 22a and 23a, respectively, at their upper ends near to the bottom end face of the regenerator 14.

Similarly, above the regenerator 14 there is an air duct member 24 which has an axial neck 25 which is disposed in rotatable, air and gas tight, engagement with the end 16 of the air duct 17, and has ducts 26 and 27 which have sector-shaped openings 26a and 27a, respectively, at their lower ends near to the upper end face of the regenerator 14.

The bottom openings 26a and 27a of the ducts 26 and 27 are opposed, in the axial direction of the regenerator, to the upper openings 22a and 23a of the ducts 22 and 23, respectively, that is, the openings 26a and 27a of the ducts 26 and 27 are disposed in mirror-image manner to the openings 22a and 23a of the ducts 22 and 23, so that air emitted from the ducts 26 and 27 will pass through the regenerator and into the ducts 22 and 23.

The two air duct members 20 and 24 are both secured to a driving shaft 28 which passes vertically through an axial opening 29 in the regenerator 14 to provide a rotation drive to the duct members in known manner.

It is desirable that there be no leakage of fluid between the air ducts. 22, 23, 26, 27 and the gas chambers 12, 13 and for this purpose sealing assemblies 30 are disposed around the peripheries of the openings 22a, 23a, 26a and 27a of the ducts 22, 23, 26, 27. The sealing assembly applied to the air duct 23 is shown in detail in FIGS. 2 and 3.

A flange 31 surrounds the upper opening 23a of the air duct 23, and a frame 32 coincides with the said flange. An expansion member 33, having a section of U shape, and made of comparatively thin flexible and resilient material, for example spring steel, is secured at its edges in a gas-tight manner by clamps 34 and packing strips 35 to the flange 31 and to the frame 32.

The frame 32 also has a metal sealing strip 36 secured to it by screw studs 37, and the said sealing strip slides, during rotation of the duct members, on the surfaces of a flange 38 on the regenerator 14 and on radial ribs of the regenerator. Rollers 39, mounted externally on the regenerator, project through the flange 38 to engage the sealing strip 36 and assist the sliding movement between the sealing strip 36 and the flange 38 and the ribs of the regenerator.

Bolts 40, spaced apart at suitable intervals around the sealing assembly, are screwed into the frame 32, and pass freely through the flange 31 on the air duct 23 and also through a second flange 41 on the air duct. Helical compression springs 43 are disposed around the bolt 40 and between the flange 41 and a cup member 45 on the bolt. Thus, the frame 32 together with the sealing strip 36 is constantly urged by the springs 43 towards the regenerator 14. A stop nut 46 on the bolt abuts the flange 41 in order to limit the movement of the bolt. The pressure of the springs 43 on the sealing strip 36 can be adjusted by rotating the screwed bolt 40 in the frame 32. Damper springs 42 are disposed between the flange 31 and other cup members 44 on the bolts.

The frame 32 and the air duct 23 also are connected to each other by swivelling connections 48 which comprise a rod 49 connected at its ends by ball-joints to brackets 50 and 51 secured, respectively, to the frame 32 and to the air duct 23.

The pressure of the springs 43 around the air ducts 22, 23 of the lower rotatable duct member 20 is adjusted so that the springs do not carry much more than the weight of the sealing frame 32 and sealing strip 36, and therefore the sealing strip 36 is in relatively light contact with co-acting sealing surfaces of the regenerator 14, the main part of the necessary contact pressure being provided by the pressure difference between the air in the ducts 22, 23 and the gas in the chamber 12.

Such a construction provides a gas-tight seal between the stationary regenerator end surfaces and the rotating air ducts. The rotational movement of the air ducts is applied to the sealing strips 36 and the frames 32 therefor by the carrier swivelling devices 48 which enable the sealing frames 32 to move axially as well as rotationally. The bolts 40 which locate the springs 42, 43 do not carry the sealing frame 32 and therefore they are not subjected to bending or jamming. A simple sealing means is provided.

During the rotating movement of the air ducts and the associated parts, each expansion joint device 30 seals off the interior of the air duct from the flue gases in the external chamber 12 and produces a flexible and resilient connection between the air duct and its associated sealing frames 32.

The pressure of the springs 43 on the sealing frame 32 and the sealing strip 36 can be adjusted by rotation, clockwise or counterclockwise, of the bolts 40. Such pressure of the springs 43, and wear of the sealing strip 36, are limited by a flanged end 52 of the nut 46 abutting the flange 41. The position of the nut 46 on the bolt 40 can be locked by a lock nut 53.

It is desirable that the clearance a between the flange 41 and the end 52 of the nut 46 should be about 5.0 mm., to allow that amount of axial movement of the bolt 40 before further such movement is limited. However, if this limited clearance is fixed before starting-up of the heat exchanger, the increasing heat expansion during the starting-up period, and until such time as the regenerator attains a stable temperature at full-load operation, causes the clearance to be varied.

Any adjustment of the nuts 46 and 53, to readjust the clearance a, is almost impossible, because such adjustment would require the operation of the heat exchanger to be stopped for such a period of time that the temperature and the clearance a would again change.

Therefore, according to the present invention, adjustment of the clearance a is effected by placing a slide 54 (shown in FIG. 7) between the nut 46 and the flange 41, a slide of appropriate thickness being selected for this purpose.

For example, if it is desired that the clearance a should be 5.0 mm. when the heat exchanger is operating normally at full load, the initial clearance, before starting-up of the heat exchanger, could be adjusted so as to amount to 8.0 mm. Then, upon the stable temperature of the heat exchanger being attained, at full load, rotation of the air hoods can be stopped momentarily so as to measure the actual clearance at that moment and to enable a slide 54 of appropriate thickness to be slipped around the bolt 40 and between the flange 41 and the nut 46 to bring the clearance a to 5.0 mm. Such momentary stopping of the heat exchanger will not create any appreciable drop in temperature or further change in the dimension of the clearance a.

In order to allow the slide 54 to be placed easily in position, and retained in that position, guides are provided on the flange 41, the guides comprising metal blocks 55 welded to the face of the flange 41 and thinner metal strips 56 secured to the blocks 55 and projecting therefrom towards the bolt 40 so as to provide ledges which form slideways on the flange 41. The slide 54 is then placed in position, with the thin edge portions 57 thereof sliding into the spaces between the flange 41 of the strips 56, as shown in FIGS. 4 and 6. After the slide 54 is placed in position, the ends 58 of the strips 56 can be bent up, to prevent the slide moving away from its position spontaneously, as shown in FIG. 6.

By effecting such adjustment of the clearance a to the desired amount, after the heat exchanger has attained a stable temperature at full load, whereby to provide an exact limitation of the axial movements of all of the bolts 40 around the sealing frames 32, equal wear of the sealing strips 36 throughout their length is assured.

Each of the bolts 40 may be rotated in the sealing frames 32 by means of a bar 59, a tommy bar, which is passed through a transverse hole 60 in the bolt, the bolt being locked against further rotation by engaging the tommy bar 59 in a slotted bar 61 which is welded to the flange 41.

What I claim and desire to secure by Letters Patent is:

1. A rotary regenerative heat exchanger comprising a casing, a hot gas inlet chamber at one end of said casing, a gas outlet chamber at the other end of said casing, a stationary regenerator within said casing between said chambers, a mass of plates in said regenerator providing a multiplicity of axial passages therethrough an outlet air duct one open end of which is disposed within said gas inlet chamber, an inlet air duct one open end of which is disposed within said gas outlet chamber, rotatable air duct members at each axial end of said regenerator having necks disposed in rotatable air and gas tight engagement with the open ends of the inlet and outlet air ducts, each air duct member having ducts with openings at their ends adjacent the axial end faces of said regenerator whereby air emitted from said inlet air duct passes through said regenerator into said outlet air duct, and sealing assemblies disposed around the peripheries of the openings of said air duct members, each sealing assembly comprising a sealing member, a frame attached to said sealing member, an expansion member between said air duct member and said frame, swivel joint means between said air duct member and frame for transmitting the rotational movement of said air duct members to said sealing member, and resilient means urging said frame from said air duct members toward said regenerator, said resilient means comprising a series of bolts disposed at spaced intervals around and secured to said frame, spring means around each said bolt and urging the bolt axially thereof together with the said frame towards the regenerator, each bolt passing freely through a flange on the air duct member, the end of the bolt remote from the said frame being provided with a flange which normally is disposed with a clearance from the flange on the air duct member and is adapted to abut said flange on the air duct member whereby to limit said axial movement of the bolt, characterised in that a slide of appropriate thickness is placed between the flange on the bolt end and the flange on the air duct member whereby to adjust the dimension of the said clearance to a desired amount of, for example, 0.5 mm.

2. A rotary regenerative heat exchanger according to claim 1, wherein guideways are provided on the flange on the air duct member to receive the said slide.

3. A rotary regenerative heat exchanger according to claim 2, wherein the said guideways comprise channelshaped elements having flanges which provide ledges to receive the edges of the slide, the said flanges being bent over at their ends to provide stops to prevent withdrawal of the slide.

4. A rotary regenerative heat exchanger according to claim 2, wherein each said slide has edge portions which repose with an easy fit in a said guideway, and a medial portion having a thickness appropriate to ability to adjust the said clearance to the desired amount.

References Cited by the Examiner FOREIGN PATENTS 919,992 2/1963 Great Britain.

ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner. 

1. A ROTARY REGENERATIVE HEAT EXCHANGER COMPRISING A CASING, A HOT GAS INLET CHAMBER AT ONE END OF SAID CASING, A GAS OUTLET CHAMBER AT THE OTHER END OF SAID CASING, A STATIONARY REGENERATOR WITHIN SAID CASING BETWEEN SAID CHAMBERS, A MASS OF PLATES IN SAID REGENERATOR PROVIDING A MULTIPLICITY OF AXIAL PASSAGES THERETHROUGH AN OUTLET AIR DUCT ONE OPEN END OF WHICH IS DISPOSED WITHIN SAID GAS INLET CHAMBER, AN INLET AIR DUCT ONE OPEN END OF WHICH IS DISPOSED WITHIN SAID GAS OUTLET CHAMBER, ROTATABLE AIR DUCT MEMBERS AT EACH AXIAL END OF SAID REGENERATOR HAVING NECKS DISPOSED IN ROTATABLE AIR AND GAS TIGHT ENGAGEMENT WITH THE OPEN ENDS OF THE INLET AND OUTLET AIR DUCTS, EACH AIR DUCT MEMBER HAVING DUCTS WITH OPENINGS AT THEIR ENDS ADJACENT THE AXIAL END FACES OF SAID REGENERATOR WHEREBY AIR EMITTED FROM SAID INLET AIR DUCT PASSES THROUGH SAID REGENERATOR INTO SAID OUTLET AIR DUCT, AND SEALING ASSEMBLIES DISPOSED AROUND THE PERIPHERIES OF THE OPENINGS OF SAID AIR DUCT MEMBERS, EACH SEALING ASSEMBLY COMPRISING A SEALING MEMBER, A FRAME ATTACHED TO SAID SEALING MEMBER, AN EXPANSION MEMBER BETWEEN SAID AIR DUCT MEMBER AND SAID FRAME, SWIVEL JOINT MEANS BETWEEN SAID AIR DUCT MEMBER AND FRAME FOR TRANSMITTING THE ROTATIONAL MOVEMENT OF SAID AIR DUCT MEMBERS TO SAID SEALING MEMBER, AND RESILIENT MEANS URGING SAID FRAME FROM SAID AIR DUCT MEMBERS TOWARD SAID REGENERATOR, SAID RESILIENT MEANS COMPRISING A SERIES OF BOLTS DISPOSED AT SPACED INTERVALS AROUND AND SECURED TO SAID FRAME, SPRING MEANS AROUND EACH SAID BOLT AND URGING THE BOLT AXIALLY THEREOF TOGETHER WITH THE SAID FRAME TOWARDS THE REGENERATOR, EACH BOLT PASSING FREELY THROUGH A FLANGE ON THE AIR DUCT MEMBER, THE END OF THE BOLT REMOTE FROM THE SAID FRAME BEING PROVIDED WITH A FLANGE WHICH NORMALLY IS DISPOSED WITH A CLEARANCE FROM THE FLANGE ON THE AIR DUCT MEMBER AND IS ADAPTED TO ABUT SAID FLANGE ON THE AIR DUCT MEMBER WHEREBY TO LIMIT SAID AXIAL MOVEMENT OF THE BOLT, CHARACTERISED IN THAT A SLIDE OF APPROPRIATE THICKNESS IS PLACED BETWEEN THE FLANGE ON THE BOLT END AND THE FLANGE ON THE AIR DUCT MEMBER WHEREBY TO ADJUST THE DIMENSION OF THE SAID CLEARANCE TO A DESIRED AMOUNT OF, FOR EXAMPLE, 0.5 MM. 